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Use inodes to compare DMA-BUFs

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The file descriptions are only equal to each other if the producer
has dup'ed the same FD.
This commit is contained in:
Simon Ser 2021-07-05 19:32:26 +02:00
parent eb5972ccf6
commit 84dd1e6542
1 changed files with 22 additions and 14 deletions
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36
src/rendervulkan.cpp
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@ -1,12 +1,11 @@
// Initialize Vulkan and composite stuff with a compute queue
#include <unistd.h>
#include <stdio.h>
#include <string.h>
#include <unistd.h>
#include <sys/stat.h>
#include <array>
#include <sys/syscall.h>
#include "rendervulkan.hpp"
#include "main.hpp"
#include "steamcompmgr.hpp"
@ -223,21 +222,30 @@ int32_t findMemoryType( VkMemoryPropertyFlags properties, uint32_t requiredTypeB
return -1;
}
// Copied from <linux/kcmp.h>
#define KCMP_FILE 0
static bool allFileDescriptorsEqual( wlr_dmabuf_attributes *pDMA )
static bool allDMABUFsEqual( wlr_dmabuf_attributes *pDMA )
{
pid_t pid = getpid();
if ( pDMA->n_planes == 1 )
return true;
struct stat first_stat;
if ( fstat( pDMA->fd[0], &first_stat ) != 0 )
{
perror( "fstat failed" );
return false;
}
for ( int i = 1; i < pDMA->n_planes; ++i )
{
// kcmp returns -1 for failures, 0 for equal, >0 for different
if ( pDMA->fd[0] != pDMA->fd[i] &&
syscall( SYS_kcmp, pid, pid, KCMP_FILE, pDMA->fd[0], pDMA->fd[i] ) > 0 )
struct stat plane_stat;
if ( fstat( pDMA->fd[i], &plane_stat ) != 0 )
{
perror( "fstat failed" );
return false;
}
if ( plane_stat.st_ino != first_stat.st_ino )
return false;
}
return true;
}
@ -474,7 +482,7 @@ bool CVulkanTexture::BInit( uint32_t width, uint32_t height, VkFormat format, cr
{
// TODO: multi-planar DISTINCT DMA-BUFs support (see vkBindImageMemory2
// and VkBindImagePlaneMemoryInfo)
assert( pDMA->n_planes == 1 || allFileDescriptorsEqual( pDMA ) );
assert( allDMABUFsEqual( pDMA ) );
// Importing memory from a FD transfers ownership of the FD
int fd = dup( pDMA->fd[0] );